


One Piece >>> Haikyuu!!

by mikkimouse4271



Category: Haikyuu!!, One Piece
Genre: Gen, Karasuno Family, Mugiwara no Ichimi | Straw Hat Pirates, Tumblr Prompt, two of your favorite shows swap AU
Language: English
Status: Completed
Published: 2018-08-28
Updated: 2018-08-27
Packaged: 2019-07-03 14:42:40
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,126
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15820989
Author URL: https://archiveofourown.org/users/mikkimouse4271/pseuds/mikkimouse4271
Summary: This was originally supposed to be a short fic written to answer an ask on tumblr, but it turned out so much longer than I expected wow. I decided to post this fic in the end.  The prompt was "two of your favorite shows swap AU" and I knew I had to do One Piece and Haikyuu. So this is my interpretation of a show swap!





	1. Chapter 1

It was finally here: an official match with the Marines. Every since the matchups were posted, the Straw Hats had been practicing nonstop. Their opponents were famous for being the toughest and most oppressive team. So, Nami, per usual, set very strict guidelines and goals for her team because there was no way she was going to lose to them.

On the morning of the match, Nami packed all the necessities and made sure she had enough time to pick up Robin on her way, including traffic. In about 10 minutes, she stopped in front of Robin’s house and saw that Robin was already waiting on the steps. 

“Robin! Good morning!” 

“Good morning, Nami,” Robin replied with a smile. She opened the passenger door and slided in. 

“Are you ready for today? Did you have a good night’s sleep? Eat a balanced breakfast?” Nami asked. Robin nodded. 

When they arrived at the parking lot, they were greeted by the unsightly scene of the rest of their teammates competing to see who could eat 40 pieces of chicken nuggets the fastest. It was Luffy. He ate so fast he started to not so subtly steal from Usopp, Sanji, and Zoro. 

“Oi!” They all yelled at him. Thus, it ended in a chase as Luffy ran from them, laughing loudly and proudly. 

Nami sighed from inside the car. “It’s like they’re not playing the biggest game of their high school career today! And why are they stuffing themselves right before we have to warm up?!!” Robin chuckled as Nami continued to list all the different ways their team was doing everything wrong. Eventually, they got out of the car and Nami angrily stormed her way to the group of idiots. 

“HEY.” 7 heads turned. The 4 people who were eating had the biggest  _ oh shit _ looks on their faces with the exception of Sanji, who was jumping and running with joy and shouting, “Nami-swaaaaaaaan! Robin-chwaaaaaan!” Nami ignored it and dodged him, so he ran into a pole. “What is wrong with all of you?!!” The exasperation was very apparent in her tone. “We have to warm up right now and you guys have full stomachs. You’re going to get a stomach ache while you’re playing.” 

Luffy tried to defend himself. “But---”

“No buts.” Nami interjected. “Let’s go inside so you can change and get ready.”

After changing, the team gathered on the gym floor. Brook plugged his phone into the speaker and played Vivaldi’s spring. Then, everyone got in a line and ran 25 laps around the court. They did the basic stretches: biceps, triceps, and quads. Soon, the gym was filled with thousands of spectators watching from above. Nami called everyone over to the side to give a talk. 

“Ok guys.” Despite the reckless morning, Nami had faith and determination in her eyes. “You know how it goes. We’re serving first, so hit the other side with everything you got. I don’t care what you do, don’t let the ball drop.”

The Straw Hats put their hands together. “One, two, three, GOING MERRY!”

The team walked with pride onto the court. They lined up, jogged to the end of the net, and gave the other team firm handshakes with very strong implications. The line-up was the usual: Franky (7) as setter in position one,  Zoro (2) as right side hitter in position two, Brook (11) as middle in position three, Sanji (3) as outside hitter in position four, Chopper (13) as libero in position five, and Luffy (1) as captain/outside hitter in position five. Robin (5) was also a middle, but she sat out in the first play because libero was in. 

“Um,” Usopp (8) mumbled weakly. “I-I think I’m coming down with a disease right now. It’s the I-don’t-think-I-can-play-because-my-stomach-is-dying disease.” He kneeled over and clutched his stomach, wailing on the floor. “Nami...help meee please.”

Nami glared at him, unimpressed. “Serves you right for eating 40 nuggets before a big game. It’s not my fault you don’t have steel stomachs like those three.” Nami, Robin, and Usopp glanced over at Luffy, Zoro, and Sanji. They looked perfectly fine. Luffy was even jumping up and down, bursting with energy. “Whatever, it’s fine. You’re our pinch server anyway, so we won’t really need you out there in the beginning. Just go sit and wait until the pain goes away.” Usopp groaned. 

A whistle sounded and Franky got ready to serve. “HEREEE IT COMES,” he shouted at the top of his lungs. It was a good thing Franky and Sanji knew how to do a jump serve. The ball was smashed over the net with great speed, but the libero on the other team, Lucci, passed it efficiently to the setter. Franky furrowed his brows. The other team returned with a strong hit and Chopper cleverly dodged, seeing that the ball would’ve been out. It was a back and forth scene. After each successful rotation, Chopper switched out with Brook and Robin. Then came Luffy’s serve. 

This was always a wonder to see because there’s no physics that could possibly explain it. Luffy bounced the ball twice. Then, he held it up to his face like he was having a staring contest with it, even after the whistle sounded. Finally, he tossed it up, pulled his right arm back, and  _ punched _ it. Even the other team was shocked for a moment. Sengoku the captain recovered first and yelled at his teammate. 

“ **GARP. IT’S YOUR DAMN FAMILY AGAIN.** First we go up against Sabo and his ridiculous setting. Then we play against Ace with his reckless, unpredictable hits. Are you kidding me?!!”

Garp snickered. “Oops. Sorry I guess.” 

The Marines were still slightly fazed, so at the last second, the best pass Lucci could do went back over the net as a free ball. Luffy smoothly made an overhead pass to Franky. Franky set to the right for Zoro, who slammed it over. Somehow, it went right, way outside of the court and was out. 

“ZORO WHAT THE HELL,” yelled Sanji. “You had  _ one _ job. How did you manage to aim the ball to the right when you’re on the right side of the court??? You dumbass marimo.”

“Huh, excuse me?” Zoro glared back at Sanji with a challenging look. “You think I MEANT to do that? You’re the one that hit it all the way back outside of the court a couple of rallies back. Why can’t you keep it inside either?” 

Nami called for a timeout before things could escalate. When the team came over, she said, “Stop arguing. It already happened, it’s over. All we have to do is get that point back. By now, you should know what each hitters habits are and be able to read the sets more clearly. You see #4? He really likes hitting straight, so block him directly in front and he’ll either be shut down or switch to hitting a cross and Chopper will be there to receive. Got it?”

“Got it!” The Straw Hats cheered and went back onto the court. Robin and Brook continued to block superbly and the hits and passes became less sloppy over time. Franky slipped every once in a while, but as the match went on, he got bolder and bolder with dumps and quicks. The first set passed, going to the Straw Hats. The second set went to the Marines overwhelmingly with a score of 25 - 18. Nami was starting to get nervous during the third set. It was 18 - 15 in favor of the Marines. 

“Usopp,” Nami called. He looked at her. “How are you feeling?”

Usopp grinned. “Great. I feel really good.” 

“Good.” Nami signaled for a player switch just as Sanji was preparing for his serve. “Get us so far ahead they won’t know what to make of it.”

Usopp took Sanji’s place and Sanji patted him on the back. “You got this, Usopp,” he said. Usopp gave him a shaky thumbs up. He looked back at Nami and gave her an even shakier thumbs up. A mantra played in his head.  _ It’s fine. Everything’s fine. I can do this. _ After a deep breath, Usopp licked his pointer finger and put it up. The whole knew this was coming, but it didn’t stop them from it questioning again. 

“What is he  _ doing? _ ” cried Nami, under her breath. “There’s no freaking wind! We’re inside a building for god’s sake.” 

Usopp knew it was weird, but oddly enough, it helped him concentrate. He had

this freaky aim that could always throw people off. The ball went up and he served a floater at the spot between the back left and middle. As expected, both players went for it and ended up bumping into each other. The crowd went wild. Another floater. This time, it hit the net exactly how Usopp wanted it. Just enough force to tip it over. He did a smug pose as he watched the front row dive for it. In the end, he turned the set around until it was 20 - 18 in favor of the Straw Hats. 

Back on the bench, Nami squealed and crushed Usopp with a hug. “5 points!!!!! You got us 5 points and now we’re in the lead by 2!!!” 

“Y-Yup,” he choked out. “No...problem...Can’t...breathe…” 

After Usopp’s serves, everyone was on alert and focused. Sanji made not one or two but  _ three _ miraculous saves with his feet. It seemed like his feet had a faster reaction time than any other part of his body, including his brain. Combined with Franky’s nimble sets and Robin’s daunting blocks, the Straw Hats managed a victory against the Marines: 25 - 23. The gymnasium erupted in applause and shouts. 

“Incredible! Absolutely incredible!” A reporter announced the results to the world. “The Straw Hats have managed to defeat the immovable Marines! What a spectacular scene!” 

The Straw Hats cheered and screamed with joy all the way to the parking lot. 

“We won. We won!!” Usopp picked Chopper up and spun him around in circles. Zoro and Sanji argued over who the better spiker was, but agreed that it was a team effort (for now) and fist bumped. In high spirits, the group happily made their way to their vehicles. 

“Alright!” Luffy turned to make an announcement. “It’s time. TIME FOR FOOD!”


	2. Haikyuu >>> One Piece

**Summary for the Chapter:**

> Last chapter was the Straw Hats in the Haikyuu world. Now it's the Karasuno team in the One Piece world!!

“An island! I see an island!” The Karasuno crew was lounging about on their ship,  the Black Crow, when Hinata announced the sighting of land. Tanaka and Noya immediately rushed to his side, making fake binoculars with their hands.

“Do they actually think that gives them the ability to see farther…” muttered Tsukishima. Yamagachi covered up a laugh. 

The island turned out to be prehistoric, still loaded with plenty of species of dinosaurs. Hinata, Noya, and Tanaka saw the long neck of a brontosaurus and turned their heads in sync to stare at Tsukishima. 

“What?” He retorted. “See a sign that says ‘Island of Idiots’?” Then, he heard the cry of a velociraptor and his face fell. “Oh no, damn it.” 

The trio snickered. “Think you can communicate with them?” teased Tanaka. 

“Or maybe he’ll find family here,” Noya added. 

Hinata had no idea how to insult someone, so the best he came up with was “I-I bet he’d get beaten up by some other dinosaur.”  

“Tsukki’s better than all those other dinosaurs! You guys already know how big his zoan devil’s fruit can make him! Obviously--”

“Shut up, Yamaguchi,” Tsukishima interrupted. 

Yamaguchi laughed sheepishly. “Sorry Tsukki.”

The door to the kitchen burst open. Suga waltzed out with a beam of satisfaction on his face. “Hey guys! Shimizu finished cooking, lunch is ready!” As if they were trained under Pavlov, Noya and Tanaka jerked their heads towards the kitchen and ran for it, breaking down the door in the process. Hinata saw Kageyama coming down the stairs from the loft, yawning the entire way down. He made his way over. 

“I can’t believe you slept until noon,” Hinata commented as they walk into the kitchen. 

“Well I  _ was  _ the one training with you until late last night,” he replied. “Or well, early morning. Twilight? Whatever. Have you gotten any better at transforming?” 

Hinata chose to look anywhere except Kageyama’s face. “Well...I’ve been trying really hard, but it feels so unnatural without you there to wield me…” 

“And how am I supposed to wield you if you can’t even turn into a simple sword or shield?” 

“Don’t be so hard on him,” said Daichi from the other end of the table. “He’s trying his best and he really is still a beginner. When did he eat his devil’s fruit again? A month ago? 3 weeks ago?” 

Kageyama’s face turned red and he lowered his head. “Yes captain.” 

Kiyoko set multiple plates of food in the middle of the table: chicken, beef, vegetables, and salmon. “Make sure you guys wash your hands before eating.” Hinata and Kageyama raced to the bathroom. Their shouts were still audible from all the way across the ship.  _ Why are you racing me!  _ **Why are you racing** **_me_ ** **?** _ I was gonna go first.  _ **Well maybe I wanted to go first!** Tsukishima expressionlessly stared at the direction of the noise. “Why are they even arguing about that?” Yamaguchi shrugged.

Narita scowled as he walked into the kitchen. “Tanaka, Noya. Did you break the door  _ again _ ?” 

“There goes more money spent on two clumsy idiots…” murmured Kinoshita, right behind Narita. He sat down at the table with a sigh. “Tanaka I’m not surprised. You use brute force with everything. But Noya! For someone who is so good at defending and protecting, how do you manage to rip a door apart?” 

“Hey,” Noya said defensively. “Why would I make a barrier against me and my own buddy? I’m not trying to break our faces. And besides! We have such great mechanics, you and Na--” 

The ship suddenly shook and dishes slid off the table. Everyone groaned. 

“Why do we always get attacked while we’re eating? It’s such a waste of food! I even helped Shimizu cook today!” Suga stormed out of the kitchen and went straight into his room, the doctor’s room. Tsukishima and Yamaguchi were already outside. 

“Yamaguchi. Are you ready?”

Yamaguchi opened a trunk on the deck and reached in for his rifle. “Hell yeah.” 

Tsukishima transformed into a large velociraptor and Yamaguchi climbed on his back. They took off into the sky and began shooting at the enemy. “Tsukki! Holy--! They have 5 whole ships. That’s basically an army, geez.” With that information in hand, Yamaguchi turned around and shot his gun at the edge of the ship 5 times. Back at the bottom, Daichi and Tanaka were getting ready.

“Ok! You heard him!” Daichi shouted. “There’s 5 ships total, so we’re gonna separate into groups. Agh, Asahi is probably already out there as we speak. He’ll take one, I’ll take another. Oi, Hinata! Kageyama!” The duo surfaced just as Daichi was giving directions. “You two tag team and take the ship on the left.” They nodded. Then, Daichi hesitated, weighing the pros and cons of his idea. “Alright, Tanaka. Take Yachi with you for the last ship.”

Yachi, who was hiding behind Suga, yelped. “W-What?!! I don’t know if that’s a good idea! I’ve only recently just started to learn how to fight. I...I’m not as good as other minks because I didn’t start my training as a child…”

“Hey!” exclaimed Tanaka. “Don’t worry about it. This is a great way to get more experience. I won’t let anything happen to you, I promise.” 

“O-Ok then! I’ll try my best!” 

“Great!” Daichi said. “Narita, send everyone on their way and come back me up. Noya, Kinoshita, Shimizu. Protect the ship and fend off intruders. Ennoshita, make an escape for us!”

Narita forged a frozen path to 3 of the ships, then followed behind the captain. 

As soon as Daichi and Narita made it to their target, bullets came from every direction. Daichi’s skin morphed into stone and Narita shielded them with ice. On another ship, Tanaka punched and kicked his way into the crowd. Yachi tried to copy and learn his moves, relying on her natural warrior instinct. Hinata and Kageyama ran down the last route. Somehow, Hinata’s transformations drastically improve under and adrenaline rush and reflexes. Without even thinking, he became the perfect sword for his partner. The weight, the length, and the style were all to Kageyama’s preferences. Kageyama would never admit it, but Hinata really did a nice job this time. Smirking, he grabbed the hilt and charged, slicing and deflecting everything that came his way. 

Asahi had already taken a small boat and propelled his way to the enemy with pulsing flames. He didn’t really like to be violent, so the only way he could justify attacking was ‘the best defense is a good offense’. They attacked first and he was just protecting his family. With both fists pointed forward, he aimed specifically at the bottom of the ship and shot flames. He sighed. “At least the only damage is to the ship… Which is also unfortunate, but better than hurting others.”

Back on the Black Crow, Ennoshita calculated the best escape route to take. “Noya! How you holdin’ up?” 

“I’m great!” was the reply. “Barrier around the ship’s holding up just fine. And Suga made us tranquilizer darts to shoot at the people approaching on small boats!” Kiyoko made use of the tranquilizer serum and dipped the tips of her arrows before she took aim and shot. Noya and Kinoshita were athletically inferior, so they stuck with simple pistols. The Black Crow team defended relentlessly for a while, but eventually, the intruders stopped coming. 

“Wow,” exclaimed Suga. “They were really persistent! We were at it for almost 15 minutes! The others should be on their way back soon.”

About 5 minutes later, a velociraptor appeared from behind the clouds. Tsukishima dove at the ship and at the last second, returned to a human and everyone who fought landed gracefully on the deck. Except for Hinata, who fell face first. The whole crew looked at each other, silently, for a few seconds before erupting into cheers. 

“We did it!” cried Yachi. “I can’t believe how I fought out there!” 

“Well  _ I _ can!” Tanaka said with a grin. “See? I knew you had it in you.” 

Sliding back into their normal routine--it wasn’t like being attacked wasn’t their normal life, but--was relatively simple. Lunch was remade and resumed, but this time, everyone helped out in the kitchen. The Karasuno crew enjoyed their meal, laughing and joking with each other, not knowing that they would soon be a part of a large, unavoidable conflict. 

**Notes for the Chapter:**

> Honestly, this was much harder to write than the first chapter at first. But I realized I stumbled over the same type of writer's block for each as I was writing them. Sometimes you really just do need a little break in between writing sessions. Hope you enjoyed the swap! Once again, come by haikyuumanga on tumblr if you ever feel like it! <3

**Author's Note:**

> Come see me on tumblr at haikyuumanga and send me some writing asks! I've been trying to practice writing lately and I'm really enjoying it. Thanks for reading! <3


End file.
